import pyutil as pyu
pyu.get_local_pyinfo()

print(pyu.ps2("python-dotenv"))

from typing import List

class Solution:
  def subarraysDivByK(self, A: List[int], K: int) -> int:
    ans = 0
    prefix = 0
    count = [1] + [0] * (K - 1)

    for a in A:
      prefix = (prefix + a) % K
      ans += count[prefix]
      count[prefix] += 1

    return ans

new Solution().subarraysDivByK()